Apparatus for and method of distillation



1 Jan. 19, 1932. w. G. LAIRD APPARATUS FOR AND METHOD 0F DISTILLATION Filed Dec. 24, 1924 2 Sheets-Sheet lA 1 1 1 1|. 11111 l l L 1 Kmsx /w BEK w .SSR GENK m MM m l 'om Jan. 19, 1932. w. GxLAxRD 1,842,181

, APPARATUS FoR `AND METHOD oF bxsTILLATIoN Filed Dec.` '24, 1924 2 sheets-sheet 2 lo t o l o t on el. Il

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k l u c n ilovlntallveoooonoa0o Moreover, when operating Patented Jan. 19, 1932 UNITED s'ra'rE-s PATENT OFFICE WYILIBUKB G. LAIRD, OF NEW YORK, N. Y., ASSIGNOBfBY MESNE ASSIGNMENTS, TO HEAT TBEATING COMPANY, OF NEW YORK, N. Y., A CORPORATION 0F DELAWARE APPARATUS FOR AND METHOD OF DISTILLATION Application led December 24, 1924. Serial No. 757,788.-

The present invention relates to the art of obtaining commercial products from raw liquids. l

In my prior application, Serial No. 368,732, filed March 25, 1920, for process for the treatment of liquids with heat, I have described aV transferring diaphragms. Also, my said application discloses transferring liquid condensed from the vapor stream in one of the heat interchangers into the feed flowing toward the heater zone. According to my said application, the oil may be cracked or not, as desired.

A study of the operating records of my said invention has shown that the cases of` relatively low eiliciency have been those in which relatively a small amount of vaporizable matter has been carried in the feed current in the heat interchangers through which the mate; rial passes to the hot zone, as compared to the amount of material which it isdesired to condense in said interchangers and contained in the vapor stream' coming from said zone. on low volatile stock accordinto my said invention, the heat efficiency has een materially improved by the transfer of condensate from the outgoing material into the ingoing material, as mentioned above. The condition of low fuel eficiency, due to low volatile content of the feed, practically always exists in cracking processes as practised prior to my invention. Consequently, `the present invention, in its specific aspect, relates more particularly to oil cracking operations. l

The present application is a continuation in part of my said application 4Serial No.

' 368,732 filed March 25, 1920, now Patent No.

The principal object of the resent mvention is to assure a high fuel e cienc in the heat treatment of` liquids having re atively low volatile content at the end boiling temperature of the product desired.

In carrying out the present invention, the feed stream, consisting of both liquid and a iuid, either vapor or gas, is passed forward through heat interchanfers to a hot zone andy in counter-current relbation t0 the vapor stream coming from said zone, the countercurrent streams being separated by metal diaphragms. The liquid part of the feed is made up from `low volatile stock to which is added prior to introduction of the feed into the first heat interchanger a material which will volatilize at the end boiling point tem` perature of the desired product and under the conditions maintained in the heat interchange apparatus. By 'suitably proportioning the stock and added material in the feed the heat required for volatilization on one side of the diaphragm or diaphra ms absorbs practically all the heat released y condensav tion on the other side of the diaphragm or diaphragms of material not desired in the final product. Since the material added to the feed will be volatile in the presence of gas at the temperature existing in the rst interchanger and the material passing from the last orecoolest zonein the interchan e circuit will be substantially a commercial y pure product a minimum amount of heat need be wasted in the condenser. Also the heat absorbed by the feed in the counter-current portion of the apparatus is carried forward to the heated zone so that there is substantially no loss of heat due to condensing the undesired ortion ofthe vapor stream coming from the ot zone.

It is known to.crack oil in a. paratus includin both a 'still and a. dep e ator arrange toy return liquid 'separate from the outgoing vapors to the main body of oil beintg cracked. I have determined that better e ficiencies are obtained in cracking processes if the 'reflux from the dephle ator is not returned to the main body of oil ing cracked except after such an intervening heat treatment as shall materially alter at least its physical characteristics and rhaps in large measure also its chemical c aracteristics.

A second object ofthe present invention is the process of the to provide a process and ap aratus, preferably of the so called tank an tube ty or in other words one using a reaction cham r and .a tube or pipe still for heatin the oil to cracking tem eruture, which sha l obtain the advantage o handling the reflux from the dephlegmator in the manner just mentioned.

A third object of the invention is to improve the operation of the tank and tube process and apparatus b introducin into the tube or pi e still wit the oil to e cracked a Huid, eit er liquid or aeroform, which shall rotect the gasoline that may form in the still rom decomposition and facilitate the rapid escape of gasoline vapors from the still to the reaction chamber and from the chamber to the dephleginator.

The novel eatures of the presentinveni tion are pointed out with particularit in the appended claims. The invention itse f, however, with further objects and advantages, will best be understood from the following description taken with the accompanying drawings, in which Fig. 1 is a diagrammatic view in elevation of an apparatus according to the present invention, and adapted to operate according to present invention, Fig. 1 being partly in section.

Fig. 2 is a vertical section through the heat interchange portion of the apparatus illustrated in Fig. 1.

Fig. 3 is a section on a line 3 3 of Fig. 2, lookinoP in the direction of the arrows.

In the drawings, 6 is a pipe through which raw liquid material or stock to be operated on may be introduced into the system. In case the apparatus is to be operated according to a continuous process, a constant Stream will be fed in through pipe 6. Liquid from ipe 6 passes into a receiver or tank 8, from W ich it is taken out by a feed pum 10 and forced up through pipe 12 to the rst of the heat interchange and scrubbing trays or chambers 14 to 26 inclusive. The volatility in the presence of as of the liquid introduced into the system t rough pi e 6 is modified as desired, according to t e present invention. This may be done conveniently by liquid introduced into the tank 8 through pipe 28, the two streams of liquid from p1 6 and 28 being thoroughly mingled in eliients 8, 10 id 12 before reaching the heat interchanger Four streams of material pass through the heat interchangers 14 to 26 inclusive, such streams being se arated by suitable metal partitions or con uits. The course of the ingoing feed through chambers 14-26 is indicated diagrammatically in Fig. 1 by series of inclined dotted lines, 14de-26a inclusive. This feed includes .not only the mixture of liquids mentioned above, but also a gas which is introduced into pipe 12 in a manner hereinafter mentioned. Aa appears clearly in Fig. 1, the feed passes from the inlet end of pipe 12 throu h the chamber 14, and is conveyed from c amber 14 to chamber 16 by a connectin pi 30. Identical pipes 30 conneet the c am r 16-26 in series as is clearly indicated on the drawings. Feed which has passed. through the series of chambers or interchangers 14-26, as indicated by the inclined dotted lines 14a-26a, (Fig. 1 leaves chamber 26 by means of pipe 32. 'pe 32 conducts the feed to a heating coil 34 in furnace chamber 36. In coil 34 the material is heated to cracking temperature, and then discharged through pipe 38 into a cracking chamber 40. The maJor portion of the cracking occurs in the chamber 40, owin to the time required for the reaction to completed. Vapors from the chamber 40 ass out throu h dome 42 and pipe 44, and t ese pass up t rough chambers- 26-14, countercurrent to the incoming feed. The path o f the vapors through chambers 26-14 is indicated diagrammatically in Fig. 1 by the wavy dotted lines 2619-141). The vapors are conducted from one chamber of the series 14--26 to the next through identical connecting pipes 46, 46. From the top chamber 14 vapors ass ofi' throu h pipe 48 to condenser 50. he cooling e 'ect of the ingoin feed condenses certain materials in the c ambers 14-26, and these condensates may be taken off to the extent desired, to serve as finished products. Gondensates from chamber 14 ma be run off through pipe 52 and trap 54 an pi 56 to condenser 5.0, and there mingled wit the condensate formed from vapors passin into the condenser, or they may be drawn o through pipe 58, suitable valves in pipes 56 and 58 permittin this condensate to be discharged where esired. When so desired, condensates may also be taken off from chambers 16 and 18 through trapped pipes 60 and 62, respectively.

Gases not condensed in condenser 50 are drawn off through pipe 64 by as pump 66 and forced into the feed line 12 t rough pipe 68. Supertluous gas may be withdrawn from the system through an outlet connected to pipe 64. In starting up the aplparatus, it is preferred to fill the system wit gas through pipe 70, rather than wait for the desired amount of gas to build up during the operation.

Condensates formed in the tra s 14--26 and not drawn off as product, flow ack from one heat interchanger of the series t0 the next through a series of connecting pipes 72, 72 and are taken out from the bottom of the lowest chamber 26 through pipe 74. For practical reasons itis preferred to derive the liquid for modifying the feed, and previously described as introduced into the raw liquid feed line from pipe 28, from the condensate or reflux flowing out through i 74. Preferably this reflux is turnedt rou sh rip@ `up through the chambers 26-14, its

76 into chamber 26, this reflux then passin at throu h each of these chambers being indicated y broken horizontal lines 26o-140y respectively. The, stream of reflux-,which 1s paed up through chambersJ26-14 is led from one chamber of the series to the nextthrough` a set of identical connecting pipes 78, 78. In continuous operation, reflux passes out of 10 top chamber 14 throu h pipe 80, which leads into pipe 28 previous y mentioned. `I do not limit myself, however, to passing the Areflux back through trays 26-,-14, but may lead this reflux' through valved pipe 77 directly Lintol pipe 80, for purposes hereinafter described.

As much as circumstances r uire of thereflux in vpipe 80 may be passed t rough a cooler venient an 82 onits wayto pipe 28 and tank 8 suitable valves being rovid'edto permit thereflux to` pass throug or b pass the` cooler.

he stream of re ux passing up through chambers 2.6-14 delivers a large proportion of the heat contained therein to the incoming feed. The main object, however, of utilizing the reflux is to provide volatilizable material in the feed stream, as previously mentioned. I donot limitmyself to theuse of reflux from heat interchangers or like cplumn chamber or tray apparatus for mixin with the ingoin feed, butl this material 1s'consuitable for the purpose when.

l i operating in accordance with the present invention. As the reflux material under lconsideratlon 1s taken 1n a l1 u1d condition from the lowermost and there ore the'hottest one of the chambers or trays 14-26, it may seem improbable that this material, when fed along with other material into the uppermost 'and therefore the coolest one of these trays would volatilize'sufliciently to give coolingv .effect inthe uppermost tray. It has been demonstrated, however, that this is the case,v

and vI 4attribute this effect to the action of the gas which forms a part of the incoming feed, as reviously described. `The incomingliqui being heated in the trays 14---26` in the presence of a gas whichhas been stripped in condenser of material volatile at the temperatures in the trays or chambers, evaporates intothe gas in much the same degree as might b e the case if the feed were exposed to va vacuum at the temperatures within trays 14--26. This effect is well known in other circumstances, 'andlis referred to as the development of partial pressures.

One of the heat losses common in distilla- I tion processes is that'caused by the rejection of hot residuum. In my prior application, Serial No. 368,7 32 above referred to, I have disclosed a method of transferring the heat of the residuum mostly to the incoming feed by passing a stream of residuum countercurrent to the feed.. I utilize this same principle in the apparatus when operating accord-l mg to the present invention,

y withdrawing a certain amount of residuum from chamber 40 through pipe 84, havin trap 86 therein. The residuum is delivere by pipe 84 into the lowermostchamber 26, and passes through 'the successive chambers 26-14 in K of the upper chamber 14 through pipe 88,

andl may be conducted to storage or otherwise treated as desired. Residuum may also be drawn off of cracking chamber 40 through pipe 90, connected to pipe 84 adjacent to trap 86, whenever the temperature conditions in trays 14--26 render it desirable to do so.

In order to prevent gases and vapors delivered to the still 40 through pipe 38 from passing directly to a vapor dome 42 and outlet pipe 44, or in other words short circuiting the cracking or reaction chamber, I prefer to place within tank or cracking chamber 40 an internal hollow cylinder 92, indi.- cated in Fig. 1 by dotted lines. At one end cylinder 92 is formed with an elbow or` 90 bend 94, the open end of which is directed downwardly above the deliver end of pipe 38. Material delivered to crac ing chamber 40 through pipe 38, therefore, is ro'ected at 'considerable velocity into the en o the cylinder 92, near the outlet 42, and asses thence through cylinder 92 to the en of tank 40 opposite outlet 42, whereby shortcircuiting of gases and vapor from pipe 38 to pipe 44` is e ectually prevented, cylinder 92 also en- `ables the vapors and gases to separate cleanly from the heavier material which collects in chamber 40. Moreover, the as in the system is thus enabled to effectively scrub the residuum in chamber 40 of all light material and carry the same to the condenser. Tank 40 is preferably provided with a draw off 96 through which carbon or other undesired ma-v terial may be discharged from the cracking zone when desired.

The interchangers 14-26 are shown in detail in Figs. 2. and 3.

The chambers 14-26 are all alike, but are arranged alternately right and left, in order to facilitate the flow of materials therethrough. Within each chamber 14--26 is a pair of internal diaphragme 98 and 100 respectively. The downwardly flowing stream 'of liquid feed and gas is introduced into the bottom of'the space 102 between these twg.

dia hra s b feed i 12, previously mentioiied. ghe ypipe 12) iseextended along the bottom of the space 102, and is perforated as indicated at 104 to permit a wide dispersion of the incoming feed and gas into li uids collected in chamber 102. The feed an gas passes out of space 102 in chamber 14 through a pipe 30, previously mentioned, which passes through the diaphragm 98 near the upper edge of this diaphragm and leads to the lower portion of space 102 in the next lower charnber of the series 14-26. In this way, the incoming liquid is repeatedly heated in the presence of gas by the bodies of liquid collected in spaces 102, these bodies of liquid being kept hot and at substantially constant temperatures by upwardly flowing streams of vapors, reflui:` and residuum.

The stream of vapors passing upwardly from dome 42 through pipe 44 enters a space 106 formed in chamber or tray 26 between the diaphragm 98 and one end wall'of the chamber. Pipe 44 is turned downwardly within the space 106, delivering the gases near the bottom of this s ace through a ro sette or the like 108. A ody of condensate is maintained in each ofthe spaces 106 by overflow ipes 7 2 and the trap in the pipe 74 so that the vapors entering through the rosette, must bubble'through this liquid thus facilitating the condensation in chambers 106 of the heavier portions of the vapors. From space 106, of chamber 26 the vapors pass through space 102 by means of a nest of tubes 110 and are delivered to a space 112, formed at the opposite end of tray 26 between diaphragm 100 and the other end wall of the tray or chamber. From space 112 'vapors ass upwardly through the succeeding trays by means of pipes 46, 46 previously mentioned. Surplus reflux condensed in spaces 106 and tubes 110 of trays 16-24 is carried out from spaces 106 of upper trays to the spaces 112 of lower trays by means of pipes 72. 72 previously mentioned. 'The condensate in passing from spaces 112 to spaces 106 flows through the bottom tubes 110. The vapors introduced through the pipes 46 remove the lighter constituents and heavier constituents low downwardly through the chambers. Reflux passing out of the lowermost space 106 is delivered by pipe 76, previously mentioned, to a small header in s ace 102 of chamber 26, whichl is connecte by means of three or more pipes 114 to a similar header 116 F ig. 3, in space 102 of this chain? ber. From header 116 the reflux passes upwardly through pipe 7 8 previously mentioned to header 116 in space 102 of the next higher chamber of the series 26`14,.and so to pipe 80 previously mentioned.

The arrangement for carrying the residuum from pipe 84 through the trays 26--14 is similar to that for the reflux, and comprises a header 118 in the space 102 of tray 26, header 118, being connected to another header 118 within this space by three or more Ipipes 120. From the second header 118 the re ux passes up b connecting pi 122, 122 and throu h simi ar headers an pipes 118-120 in t e spaces 102 of the remaining trays of the series 26-14 until it issues through the pipe 88 previously mentioned.

The operation of the apparatus according to the present invention and according to the present method will be obvious from the foregoing description. For purposes of convenience, however, the operation will be restated as follows: Stock is fed into the system continuously through pipe 6 and mixed with a more volatile liquid and then with gas before being introduced into the first of a series of heat interchangers 14-26 through which the feed passes on its way to a heating coil 34. In heating coi1'34, the feed liquid is brought to the temperature desired, and usually to cracking tem erature. From coil 34, the liquid and gas discharge into chamber 40 wherevin vapors and gas separate from residuum.

Vapor and gas are then passed through the heat interchangers countercurrent to the iiigoing feed. After leaving the heat interchangers, the gas is strip d of its vapors in condenser 50 and returne to the ingoing feed line. Reflux or condensate formed in heat interchangers 14-26 by artial condensation of va ors therein is pre erabl drawn from vintero anger 26 and returned t rough all the interchaners counte-current to the feed. Also resi uum from ychamber 40 is forced through interchangers 14-26 counter-current to the feed whenever desired, before being discharged from the system. The streams of ingoing feed and outgoing vapor are kept separate from all other materials within the heat interchangers by suitable means and the outgoin streams of reflux and residuum are also pre erably kept separated from each other while in the heat interchangers.

It will be seen that the heat interchanginar system comprisingthe chamber 26-14 and the parts associated therewith acts as a concentration unit superimposed on a crackin unit and operating entirel by what woul otherwise be waste heat. e concentrating operation requires considerable amounts of heat and therefore affords opportunity for using the heat of the residuum as well as that ofthe vapors heavier than the product recovered from the condenser. A remarkably favorable heat balance is therefore obtained when working with the a paratus of and according to the process o the present inven tion.

It will be seen also that the process and apparatus according to the present invention involves the use of a complete circuit running through the still and condensers for a Huid in addition to the feed, said llud being preferabl lighter than-the product to be recovered an being specifically disclosed herein as a gas. However, the present invention is not limited to the use ofa gas in this connection. X

When operating to crack oil such as gas oil or heavier according to the present invention the feed stream composed of the initial feed of gas oil or other relatively heavy oil, the light fluid, reflux, and residuum contains practically the entire range of h dro-carbons except the gasoline fraction. T e formation of gasoline in the heating coil or still 34 and in reaction chamber 40 is therefore promoted by the absence of an initial partial pressure in the gasoline range and a maximum yield is obtainedv because the gasoline vapors formed are quickly swept out'of the coil 34, and the chamber'40, and are absorbed by other hydro-carbon gases and protectedv fromV decomposition. Particular attention is called to'the fact that the -reflux material added to the feed stream is material that has been through pipe 6. The same apparatus may,

however, beloperated on the batch principle. If it is desired to do this, a suflicient amount of liquid is introduced at one time, either through pipe 6, or'otherwise, and the apparatus brought to the proper temperature and pressure,if pressure is used. When operating on the batch principle, however. it is necessary to maintain the thermal conditions within chambers 14--26 by substituting another source of fluid for that introduced through pipe 6 in the continuous method of operation. For this purpose Imix the reflux with the residuum, this may be done either by a pipe 124, connecting the pipe 88 with pipe 80, or by a 'pipe 85 connecting pipe 84 with pipe 80. Valves 126 and 128 in pipes 124 and 85 respectively permit the residuum to be discharged into the reflux pipe 80 when desired. A sucient volume of liquid may thus be introduced into the tray 14 through pipe 12 to simulate the conditionsv obtained during continuous operation. The feed under these conditions, of course, is merely a mixture of reflux and residuum, and the composition ofthe liquids in the trays will not remain constant while running 0E a given batch. Nevertheless, I find that I' can obtain high fuel efliciency with the apparatus herein disclosed when operated in accordance with the present invention on the batch-principle.

It will be seen from the foregoing that the present invention utilizes the heat of the Afuel to maximpm extent, the various individual losses havlng been reduced to a minimum.

Many features of the tray or chamber coni struction disclosed herein are illustrated in my prior application, No. 646,718, filed June 20, 1923, for process and apparatus for distillation, and are not claimed herein. Also the broad invention of evaporating material in a heat interchanger under conditions of agitation produced by a feed current containing gas is disclosed in my prior application, Ser. No. 349,262, filed January. 3, 1920, and is not claimed herein.

Having thus described my invention, I claim:

1. A method of treating liquids comprising advancing-liquid to a hot z one in heat interchanging relation to but out of contact with vapors passing from saidzone, condensing a 'higher boiling point portion of the said vapors and passing said condensate into heat interchanging relation to but out of contact with said vapors and liquid, said condensate flowing in a direction countercurrent to said liquid and adding said condensate to said liquid prior to the point at which the liquid enters into heat interchanging relation to said vapors.

2. A method of treating liquids comprising continuously advancing liquid to a hot zone in heat interchanging relation to but out of contact with vapors passingr from said zone, introducing gas into said liquid and passing the gas in contact with the liquid to the hot zone, withdrawing the gas with the vapors leaving the hot zone, condensing higher boiling point portions of the vapors and passing said condensate in heat interchanging relation to but out of contact with said vapors and liquid, adding said condensate to said liquid prior to the point at which the liquid enters into heat interchangin heat interchanging relation to but out of contact with said vapors and liquid, said condensate flowing in a direction countercurrent to said liquid, adding said condensate to said liquid prior to the point at which liquid enters into heat interchanging relation to said vapors, removing residuum from the hot zone, and circulating it in heat interchanging relation to but out of contact with said-vapors and liquid, said residuum flowing in a direction counter-current to said liquid and removing the residuum froml the stem at the end of the countercurrent 4. 'A method of treating liquids comprising flow.

continuously advancing liquid to a hot zone 1n heat interchanging relation to but out of contact with vapors passing from said zone,

introducing gas into said liquid and passing the gas in contact with the liquid to the hot zone, withdrawing the gas with the vapors leaving the hot zone, condensing higher boiling point portions of said vapors and passing sald Vcondensate in heat interchanging relation to, but out of contact with said vapors and liquid, said condensate flowing in a direction counter-current to said liquid, adding said condensate to the said liquid prior to the int at which the liquid enters into heat lnterchanging relation to said vapors, separating the gas from the remaining vapors by condensation and returning it to the liquid, removing residuum from the hot zone and circulating it in heat interchanging relation to but out of contact with said vapors and liquid, said residuum flowing ina direction counter-current to said liquid, and removing the residuum from the system at the end of the counter-current How.

5. In an apparatus for treating liquids, the combination of a reaction chamber, a dephlegmator receiving gases and vapors from said chamber, means for passing feed liquid through said dephlegmator counter-current to said ases and vapors, and means for passing reux formed inA the dephlegmator counter-current and in contact with said vapors to the hotter end of said dephlegmator and then through thedephlegmator in the same direction as said gases and vapors, but separate from both the vapors and the feed.

6. A combined dephlegmating and fractionatingapparatus comprising a plurality of units each of said units having two internal partitions, tubes connecting the spaces in each unit on the outsides of said partitions, means for leading vapors and gases through said tubes of each of said units in series, means whereby" liquid containing vaporizable material is passed in external contact with said tubes of each of said units in series and counter-current to the direction of ow of said va rs throu h the apparatus, means whereby llquid con ensed from said vapors is maintained in each unit above the level of the incoming vapors and ases, and means for leading condensed li'qui vfrom one unit to the next in the direction opposite to the flow of vapors and gases.

7. combined dephlegmating and fractionating .ap aratus comprising a plurality of units, eac of said units having two intel-nal partitions, tubes connecting the spaces 1n each unit on the outsides of said partitions, means for leading vapors and gases through said tubes of each of said units in series, means whereby liquid containing vaporizable material 1s passed in external contact with said tubes of each of said units in series and counter-current to the direction of flow of said vapors through the a paratus, means whereby liquid condensed om said vapors is maintained in each unit above the level of the incoming vapors and gases, and means for passing said condensed l1 uid through the spaces in said units interme iate said partitions in the same direction from unit to unit as said vapors and in diaphragm contact with other liquids therein.

8. A combined dephlegmating and fractionating apparatus comprising a plurality of units, each of said units having two internal partitions, tubes connecting the space in each unit on the outsides of said partitions, means for leading vapors and gases through said tubes of each of said units in series, means whereby li uid containing vaporizable material is passe in external contact with said tubes of each of said units in series and countercurrent to the direction of flow of said vapors through the apparatus, means whereby liquid condensed from said vapors is maintained in each unit above the level of the incoming vapors and lgases, means for runninghot liquid from t e same source as said vapors through the spaces in said units intermediate said partitions and in diaphragm contact with other liquids therein.

9. A combined dephlegmating and fractionating apparatus comprising a plurality of units having two internal partitions, tubes connecting the space in each unit on the outsides of said partitions, means for leading vapors and gasesthrough said tubes of eac of said units in series, means whereby 1i uid containing vaporizable material is asse in external contact with said tubes o each of said units in series and countercurrent to the direction of fiow of said va ors throu h the apparatus, means whereby iquid con ensed from said vapors is maintained in each unit above thelevel of the incoming vapors and gases, means r for passin said condensed liquid through the spaces 1n said units intermediate said partitions in the same direction from unit to unit as said vapors and in diaphragm contact with other liquids therein, and means for running hot liquid from the same source as said va rs through the spaces in said units intermediate said partitions and in diaphragm contact with other liquids therein.

10. A combined dephlegmating and fractionating apparatus comprising a plurality of units, each of said units havi two internal partitions, tubes connecting t e space in each unit on the outsides of sald partitions, means for leading vapors and gases through said tubes of each of saidunits in series,

means whereby li uid containing vaporizable material is passe in external contacta with said tubes of each of said units in series and vcountercurrent to the direction of flow of said vapors through the apparatus means whereby liquid condensed om vapors ilo is maintained in each unit above the level of the incoming vapors and gases, means for passing said condensed liquid through the spaces in said units intermediate said partitions in the same direction from unit to unit as said vapors and in diaphra m contact with other liquidsltherein, means or running hot liquid from the same source as said vapors through the spaces in said units intermediate said partitions and in diaphragm contact counter-current and in contact wlth said vapors Ato the hotter end of the dephlegmator and then through the dephlegmator in the same direction as said gases and vapors, but separate from both the vapors andthe feed, and means for putting some of said reiiux into said feed liquid prior to the entrance of the feed liquid into said dephlegmator.

12. An apparatus for distilling liquids,

` which comprises means for heatin liquid to produce distillation thereof, a dep legmator means for passing liquid to be heated through said dephlegmator as a series of connected bodies, means for conducting liquid from the last of said bodies to said heating means, means for passing vapors from said heating means, through said dephlegmator counter current to and in heat exchange relation with said liquid bodies but out of contact therewith thereby to produce partial condensation of said vapors, means for holding a portion of the condensate produced by sal'd heat exchangein heat transfer but out of contact with said liquid bodies, means for bubbling said vapors through said bodies of condensate, and means for passing gas into and for bubbling it through the liquid in said series of connected bodies. Y

13. The process of cracking oils, which comprises cracking oil in a cracking zone to' produce vapors therefrom, passing the vapors through a dephlegmatin and rectifying zone where the higher boiling portion of said vapors is condensed, passing the condensate produced in said dephlegmating zone counter current to and in contact with said vapors, passing raw charging oil tov be cracked through said dephlegmating zone in a confined circuit in heat exchange with said vapors and said condensate and mixing said condensa-te with' said. raw 'charging stock P prior to passing said stock through. said dephlegmating zone thereby to increase the i heat transfer in said heat exchange.

14. The process ofl distilling' oil, which comprises assing the oil to be distilled through a ephlegmating zone counter cur rent to oil vapors rom a distilling zone, passing refiux condensate formed in said dephlegmating-zone counter current to and in contact with said vapors to the hotter portion of said dephlegmating zone and then throughsaid dephlegmating zone in the same direction as said vapors, but maintained out of' contact therewith. Y

15. Thel method of treating liquids containing a relatively low percentage of volatile, which comprises mixing a raw low volatile' liquid with another liquid of more volatile character, passing the resulting mixture so formed in heat transferrin` relation to, but `separated from, a stream of vapors issuing from a heating zone, thereby vaporizing some of said mixture, passing the said mixture together with the vapors formed therefrom into. the heating zone fromwhich 'said stream of vapors issues, and separating from the vapors issuing from saidlzone by condensation, constituents comprising portions of'said more volatile liquid for mixing with further quantities of the raw low volatile liquid to be treated.

16. A continuous process fordistilling a liquid lcontaining a relatively small percent- `age of light volatile constituents which comprises mixing with said liquid a second liquid of more volatile character and a gas, passing the mixture through a series of heating zones of increasing temperature inindirect heat exchange with vapors passing in the opposite direction therethrough, thereby to vaporize portions of the liquid in said mixture and increase the relative amount of heat transferred from said vapors, maintaining the gas, vapor and liquid of said mixture in intimate contact with each other in said zones, further heating the mixture and introducing it into a vapor separating zone, and conducting the vapors from said zone through said heatin zones to supply hot vapors for heating sai mixture.

17. The process of cracking oils, which comprises cracking oil in a cracking zone to produce vapors therefrom, passing the vapors through a dephlegmating an rectify- "ing zone where the higherboiling portion of said vapors is condensed, passing the con-` densate produced in said dephlegmating zone counter current to and in contact with said vapors, passing rawcharging oil Y to be cracked through said dephlegmating zone in a confined circuit in indirect heat exchange with said vapors, maintaining a pressure on the charging oil substantially equal'to that maintained in the rectifying zone and mixing said condensate with said raw chargin stoc prior to passing said stock throug said dephlegmating vzone thereby to increase the heat transfer' in 'said heat exchange.

18. The process of crackin relatively hea vhydrocarbon oils, whic comprises 5 passing the oil to be cracked through a series of heat exchange` zones of increasing temperatur'e in which the oil is heated by indirect heat exchange with hot cracked vapors, maintainin certain of said zones at a i temperature suiclent to vaporize portions of Ysaid oil, passing vaporized and unvaporized portions of said oil from each Vzone in intimate f contact with each other in each succeeding y 1 zone, passing the oil and-vapors from the 15 highest temperature zoneof the series together in a co'nne'd stream through an additional high temperature heating zone in which the mixture is -subjected to acrackin temperature, discharging the oil from sai p whigh temperature heating zoneinto intimate contact with a body of oil maintained in a vapor separating zone maintaining such bodX of oil at a cracking tem rature, and passing vapor separatingthere om through U .said heat exchange zones counter current to and in indirect heat 'exchange with the oil therethrough and in contact with V l es o f condensate produced from said va ts. t

. n testimony whereof I aix my signature.

' WILBUR G. LAIRD. 

